1⼀2+1⼀6+1⼀12+1⼀20+1⼀30×1⼀42 简便计算

2025-02-25 04:13:17
推荐回答(1个)
回答1:

你的题目是否有错:
1/2+1/6+1/12+1/20+1/30+1/42
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7
=1-1/7=6/7
若按你的:
1/2+1/6+1/12+1/20+1/30*1/42
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/30*1/42
=1-1/5+1/30*1/42
=4/5+1/1260
=1009/1260